TODAY is world Sickle Cell Day. Like most other epidemiological statistics, Nigeria still takes the lead in sub-Saharan Africa with the highest cases of sickle cell births. About one per cent of every life births are babies with the sickle cell disorder. Their life expectancy is unfortunately still pegged at about 21 years. But then, there is an enormous risk group, which is about 25 per cent of the entire country’s population - those with the sickle cell trait with blood genotypes commonly seen in Nigeria as HbAS or HbAC, among others.
Despite the social awareness of the dangers of marital union between couples with the sickle cell trait - because therein lies the genetic pool for sickle cell disorder, most people still damn the consequences and proceed with such marriages anyway. Although there are medical ousts to prevent sickle cell births, now also obtainable in Nigeria - which includes Pre-natal Diagnosis (PND) and Pre-implantation Genetic Diagnosis following In-Vitro Fertilisation (IVF/PGD); the odds, uncertainties, and ethical smudges trump the desirability for most risk groups in such marriages.Then it took some necessitated thinking for a young scientist to begin the process of attempting a molecular characterisation for sickle cell sperms. The rationale hinges on the undesirability of some of the current medical ousts for preventing sickle cell births emanating from such odds as access, cost, success rate and the ethical dilemma of deciding what to do with embryos identified with the sickle cell genes. These, among other reasons, have incited the scientific community to attempt to proffer a more acceptable preventive approach for couples with the sickle cell trait.
The molecular genetics of fertilisation emphasises the union of haploid gametes - the sperm and the egg cell, both containing halved genetic information contributed by the paternal and maternal sides respectively - to make a complete diploid cell that proceeds with the rest of the cellular differentiation. The rules of dominance and recessiveness come into play with phenotypic expressions, such that couples with the sickle cell trait may both donate the autosomal recessive genes for sickle cell at 25 per cent frequency per single event of fertilisation - which summarily means, the genetic cross that yields a sickle cell birth at any given time has a chance of occurring once in four trials with such couples. It is a statistical chance, and does not necessarily mean, a child with the sickle cell disorder is born after every four births.
To make life easy for such couples, a biotechnology capable of selective contraception was conceived, which hinges on the ability of specially created monoclonal antibodies being able to disable sickle cell sperms before conception occurs. Then a definitive non-sickle cell genotype is assured or at best a further reduction of the 25 per cent chance of birthing a sickle cell baby is ensured from its use.
Then the search began in 2012 following a brief ideas’ presentation at the Sickle Cell Unit of the University of Miami’s School of Medicine in Florida, USA, where a pool of sickle cell sperm donor patients would be sought. The initial search is for a novel characterised antigen or biomarker that distinguishes a sickle cell sperm from its wild-type counterpart. The first flawed thinking among scientists would be - the antigenic differentiation for sickle cell has its domain in the hemoglobin protein sequence, and that very protein is not expressed in gamete cells.
Well, to corroborate or discredit that argument - the first point of duty was to acquire existing monoclonal antibodies sensitive enough to distinguish the HbA and the HbS hemoglobin subsets.
But the characterisation experiment is not to be carried out on blood samples but sperm samples. With profound interests in this search and being heterozygous for sickle cell with the HbAS genotype, I embarked on testing my own sperm cells with these acquired monoclonal antibodies in a refined methodology that may later culminate in an assisted conception procedure tagged Intra-cytoplasmic Genotypically Selected Sperm Injection (IGSI) - where sperm cells with the sickle cell genes may be identified under a fluorescent microscope and excluded from an IVF treatment procedure.
Or better still design a special condom device with a void, which has been embedded with monoclonal antibodies capable of identifying and binding to characterised sickle cell antigens on sickle cell sperms - thereby deactivating or immobilising them from taking part in subsequent fertilisation events at each instance of ejaculation during natural copulatory events. Maybe someday, sickle cell births can be prevented even among couples with the sickle cell trait, but then it begins with a definite characterisation of the sickle cell sperm. We may be a step away from achieving this ingenious feat today.
• Olumide Adenmosun is a young scientist and alumnus of Bowen University, Nigeria and Florida Atlantic University, USA. He is also an emerging entrepreneur working with a team of other young scientists at his start-up company Eurekan Biotechnologies. He can be reached on olucyno@gmail.comThis email address is being protected from spambots. You need JavaScript enabled to view it.
